EP4079396A1 - Device for producing bone cement - Google Patents

Abstract

The invention relates to a device 100 for preparing a bone cement dough 450 from two starting components, comprising a hollow-cylindrical cartridge 200 with an interior 210, with a bone cement powder 400 as the first starting component in a front part 220 of the interior 210 and a bone cement powder 400 in a rear part 230 of the interior 210 Container 300 containing a monomer liquid 350 as the second starting component is stored, wherein between the bone cement powder 400 and the container 300 there is a discharge piston 250 that can move axially in the interior space 210 and on the side of the container 300 that is opposite the discharge piston 250 there is a delivery piston 270 that can move axially in the interior space 210. wherein the rear part 230 and the front part 220 of the interior 210 are fluidly connected to one another via a line means 260 and by advancing the delivery piston 270 in the direction of the discharge piston 250 the container 300 by breaking up into a plurality of container parts pieces 300a can be opened, so that the monomer liquid 350 can flow into the rear part 230 of the interior space 210. The invention further relates to a method 600 for preparing a bone cement dough 450 from two starting components by means of such a device 100.

Description

The invention relates to a device for preparing a bone cement paste from two starting components, comprising a hollow-cylindrical cartridge with an interior space, a bone cement powder as the first starting component being stored in a front part of the interior space and a container containing a monomer liquid as the second starting component being stored in a rear part of the interior space. wherein between the bone cement powder and the container is a discharge piston that is movable axially in the interior space and on the side of the container opposite the discharge piston is a delivery piston that is movable axially in the interior space, with the rear part and the front part of the interior space being connected to one another in a fluid-conducting manner via a line and by Advancing the feed piston in the direction of the discharge piston, the container can be opened by breaking it up into a large number of container sections, so that the monomer liquid can flow into the rear part of the interior.

The invention further relates to a method for preparing a bone cement dough from two starting components by means of such a device.

Background of the Invention

Significant efforts are being made to identify devices and methods for providing bone cement by means of which bone cement dough can be provided easily, safely and quickly. An important aspect when preparing bone cement dough is the avoidance of air pockets in the bone cement. To avoid this, a large number of vacuum cementing systems have been described, of which the following are mentioned as examples: US 6,033,105A , US 5,624,184A , US 4,671,263A , US 4,973,168A , US 5,100,241A , WO 99/67015 A1 , EP 1020167 A2 , US 5,586,821A , EP 1016452 A2 , DE 3640279 A1 , WO 94/26403 A1 , EP 1005901 A2 , EP 1886647 A1 , US 5,344,232A .

There is a desire in the market to simplify the supply of bone cement dough. A further development consists in the development of cementing systems in which both starting components are stored in separate areas of the mixing system and are only mixed with one another in the cementing system immediately before the cementing application. Such closed, so-called full-prepacked systems are in the following writings called: EP 0 692 229 A1 , DE 10 2009 031 178 B3 , US 5,997,544A , US 6,709,149 B1 , DE 698 12 726 T2 , EP 0 796 653 A2 , US 5,588,745A .

In the EP 3 320 870 A1 a full prepack system is described, in which the container filled with monomer liquid is stored axially behind the bone cement powder within a cartridge. A discharge plunger is arranged between the bone cement powder and the container. In order to provide the bone cement dough, a delivery piston, which is arranged on a side of the container opposite the discharge piston, is advanced in the direction of the discharge piston, as a result of which the container is opened by at least partially bursting the container into container sections. The monomer liquid emerging from the container is conveyed into the bone cement powder with the formation of the bone cement dough by the continued advancement of the conveying plunger. In the process, the container is compressed further and further, sometimes with further fragmentation of the container sections, until a maximum compression is reached. It has turned out to be disadvantageous that a proportion of the monomer liquid remains between the container sections, which is not available for the formation of the bone cement dough. This proportion can vary from application to application, so that the bone cement paste provided with the device described has varying mixing ratios of bone cement powder to monomer liquid and thus varying properties, such as viscosity and curing times. This makes it difficult for the operator to use it. In addition, when the bone cement paste is discharged from the device, there may be a delayed conveying or "injection" of monomer liquid remaining between the container sections into the already formed bone cement paste, so that in particular the part of the bone cement paste facing the container sections has a larger proportion of monomer liquid compared to bone cement powder as the part of the bone cement paste facing away from the container sections and therefore the properties of the bone cement paste change in the course of the discharge. The bone cement paste facing the container is "diluted" by the subsequently introduced amount of monomer liquid and has a lower viscosity than the bone cement paste initially discharged from the device.

tasks

It is an object of the present invention to at least partially overcome one or more of the disadvantages encountered in the prior art.

In particular, the invention is based on the aim of providing devices which can provide a bone cement paste simply, safely, quickly and with a constant mixing ratio of bone cement powder and monomer liquid. The device should enable the monomer liquid to be conveyed as completely as possible into the bone cement powder, so that as little monomer liquid as possible remains between the container sections.

The device is intended to provide the bone cement without mechanical mixing of the starting components. The device should also be designed in such a way that the user does not have to carry out any assembly steps. The device should be able to provide the bone cement without externally applied vacuum. The device should be able to discharge the bone cement provided. The device should be able to discharge the bone cement provided without any modification measures. The device should be able to provide and discharge the bone cement without conversion measures and without external equipment such as hoses, vacuum sources or squeezing devices. The device should be able to be operated with as few work steps as possible in order to minimize sources of error by the user.

Another object of the invention is to provide a method with which bone cement can be provided from two starting components, by means of which at least some of the objects already described are at least partially achieved.

Preferred Embodiments of the Invention

A contribution to the at least partial fulfillment of at least one of the aforementioned objects is made by the features of the independent claims. The dependent claims provide preferred embodiments contributing to at least partly fulfilling at least one of the objects.

A first embodiment of the invention is a device for preparing a bone cement paste from two starting components, comprising a hollow-cylindrical cartridge with an interior space, a bone cement powder as the first starting component being stored in a front part of the interior space and a container containing a monomer liquid as the second starting component being stored in a rear part of the interior space,
wherein between the bone cement powder and the container is a discharge piston that is movable axially in the interior space and on the side of the container opposite the discharge piston is a delivery piston that is movable axially in the interior space, with the rear part and the front part of the interior space being connected to one another in a fluid-conducting manner via a line and by advancing the delivery plunger in the direction of the discharge plunger, the container can be opened by breaking it up into a large number of container sections, so that the monomer liquid can flow into the rear part of the interior,
characterized in that
a volume-stable displacement means is arranged in the rear part of the interior, which is designed to enclose the container sections with progressive advancement of the delivery piston in the direction of the discharge piston, with displacement of the monomer liquid between the container sections in order to move the monomer liquid from the rear part via the line means into the front part of the promote interiors.

In one embodiment of the device, the displacer is substantially insoluble in the monomer liquid at room temperature, that is, in the range of 15°C to 30°C. This embodiment is a second embodiment of the invention, which preferably depends on the first embodiment of the invention.

In one embodiment of the device, the displacing agent comprises a hard fat and/or a wax with a melting point of at least 40°C. This embodiment is a third embodiment of the invention, which preferably depends on the first or the second embodiment of the invention.

In one embodiment of the device, the displacement means comprises a large number, meaning at least two, particles with a Shore A hardness of less than or equal to 80, preferably less than or equal to 50, more preferably less than or equal to 30. This embodiment is a fourth embodiment of the Invention, which preferably depends on the first or second embodiment of the invention.

In one embodiment of the device, the multiplicity of particles of the displacement agent are spherical, in particular spherical or ovoid, in shape. This embodiment is a fifth embodiment of the invention, which preferably depends on the fourth embodiment of the invention.

In one embodiment of the device, the particles of the displacement agent are made of silicone rubber, natural rubber, polyurethane-polyester rubber, polybutadiene-styrene rubber or mixtures of these substances. This embodiment is a sixth embodiment of the invention, which preferably depends on the fourth or fifth embodiment of the invention.

In one embodiment of the device, the particles of the displacement agent have a diameter in a range from 1 mm to 3.5 mm, preferably in a range from 1.3 mm to 3.0 mm, more preferably in a range from 1.5 mm to 2.5mm, on. This embodiment is a seventh embodiment of the invention, which preferably depends on the fourth, fifth or sixth embodiment of the invention.

In one embodiment of the device, the displacement means comprises a paste containing a powdered solid and a liquid. This embodiment is an eighth embodiment of the invention, which preferably depends on the first or second embodiment of the invention.

In one embodiment of the device, the displacement agent comprises propane-1,2,3-triol as a liquid and silicon dioxide as a solid. This embodiment is a ninth embodiment of the invention, which preferably depends on the eighth embodiment of the invention.

In one embodiment of the device, the silicon dioxide comprises fumed silicon dioxide, precipitated silicon dioxide or a mixture of fumed and precipitated silicon dioxide. This embodiment is a tenth embodiment of the invention, which preferably depends on the ninth embodiment of the invention.

In one embodiment of the device, the displacement medium occupies a displacement medium volume which corresponds at least to a total volume of the container sections. This embodiment is an eleventh embodiment of the Invention, which preferably depends on one of the preceding embodiments of the invention.

In one embodiment of the device, the displacement means is arranged at least partially between the container and the delivery piston. This embodiment is a twelfth embodiment of the invention, which preferably depends on any of the preceding embodiments of the invention.

In one embodiment of the device, the displacement means is arranged at least partially radially around the container. This embodiment is a thirteenth embodiment of the invention, which preferably depends on any of the preceding embodiments of the invention.

1. a. Vortreiben des Förderkolbens in Richtung des Austragskolbens unter Zerfall des Behälters in eine Vielzahl an Behälterteilstücken,
2. b. Zusammenschieben der Behälterteilstücke durch fortgesetztes Vortreiben des Förderkolbens,
3. c. Verdrängen der Monomerflüssigkeit zwischen den Behälterteilstücken durch das Verdrängungsmittel unter Fördern der Monomerflüssigkeit in den vorderen Teil des Innenraums zum Ausbilden des Knochenzementteiges.

A fourteenth embodiment of the invention is a method for preparing a bone cement dough from two starting components by means of a device according to one of the preceding embodiments, comprising the following steps:

1. a. advancing the delivery plunger in the direction of the discharge plunger, with the container breaking up into a large number of container sections,
2. b. Pushing the container sections together by continuing to advance the delivery plunger,
3. c. displacing the monomer liquid between the container sections by the displacing means while feeding the monomer liquid into the front part of the inner space to form the bone cement dough.

In one embodiment of the method, the device is used in a discharge device to advance the delivery plunger. This embodiment is a fifteenth embodiment of the invention, which preferably depends on the fourteenth embodiment of the invention.

In one embodiment of the method, the monomer liquid is distributed in the bone cement powder with the aid of a hydrophilic additive. This embodiment is a sixteenth embodiment of the invention, which preferably depends on the fourteenth or fifteenth embodiment of the invention.

General

In the present description, range specifications also include the values specified as limits. An indication of the type "in the range from X to Y" in relation to a quantity A therefore means that A can take on the values X, Y and values between X and Y. Unilaterally delimited areas of the type "up to Y" for a size A mean correspondingly as a value Y and smaller than Y.

Some of the features described are linked to the term "substantially". The term "essentially" is to be understood in such a way that under real conditions and manufacturing techniques, a mathematically exact interpretation of terms such as "superimposition", "perpendicular", "diameter" or "parallelism" can never be given exactly, but only within certain manufacturing error tolerances can. For example, "substantially parallel axes" include an angle of 85 degrees to 95 degrees to each other and "substantially equal volumes" include a deviation of up to 5% by volume. A “device consisting essentially of plastic” includes, for example, a plastic content of ≧95 to ≦100% by weight. A "substantially complete filling of a volume B" includes, for example, a filling of ≥95 to ≤100% by volume of the total volume of B.

Detailed description

A first object of the invention relates to a device for preparing a bone cement dough from two starting components, comprising
a hollow-cylindrical cartridge with an interior space, a bone cement powder as the first starting component being stored in a front part of the interior space and a container containing a monomer liquid as the second starting component being stored in a rear part of the interior space,
wherein between the bone cement powder and the container is a discharge piston that is movable axially in the interior space and on the side of the container opposite the discharge piston is a delivery piston that is movable axially in the interior space, with the rear part and the front part of the interior space being connected to one another in a fluid-conducting manner via a line and by Advancing the feed piston in the direction of the discharge piston, the container can be opened by breaking it up into a large number of container sections, so that the monomer liquid can flow into the rear part of the interior.

In order to overcome the above-mentioned disadvantages in the prior art, the invention provides that a volume-stable displacement means is arranged in the rear part of the interior, which is designed to enclose the container sections with progressive advancement of the delivery piston in the direction of the discharge piston, with displacement of the monomer liquid between the container sections to convey the monomer liquid from the rear part to the front part of the inner space via the conduit means.

The displacement agent thus fills an intermediate space between the container sections, which is filled with the monomer liquid and/or a gas, such as air or nitrogen, after the container has been opened and the container sections have been further fragmented into smaller container sections, and displaces the monomer liquid present there. Since the rear part of the interior space is sealed in a fluid-tight manner by the delivery plunger on the side opposite the line means, the monomer liquid is pumped via the line means into the bone cement powder in the bone cement powder in the promoted front part of the interior. The device thus ensures an almost complete mixing of bone cement powder and monomer liquid, which means that bone cement dough can be provided easily, quickly and reliably with a constant
Bone cement dough composition allowed.

The device has a hollow-cylindrical cartridge. A hollow-cylindrical cartridge is to be understood as meaning a tube-like container which has an interior space and a cartridge wall surrounding the interior space. The cross section of the cartridge can take on any shape. Due to the simple production and the safer use of the device, the cross section, and preferably also the cross section of the interior, is circular. This allows good handling for the user and, due to the absence of edges, reduces a risk of moving parts becoming wedged within the device. According to the invention, the cartridge can consist of a wide variety of materials or combinations of materials. For example, the device can be made of plastic. The plastic is preferably a transparent plastic, since in this way the user can visually check that the device is functioning properly during use.

Arranged between the bone cement powder and the container is a discharge piston that can be moved axially in the interior. The discharge piston is used for the spatial separation of container and bone cement powder, so that neither bone cement powder from the front part of the interior to the rear part of the interior, nor the container or container sections after opening the container, from the rear part of the interior to the front part of the interior can reach. In particular, the latter prevents a bone cement paste interspersed with container sections, which pose health risks for the patient and could impair proper discharge of the bone cement paste from the device. The discharge plunger is also used to discharge the prepared bone cement dough from the device. For this purpose, the discharge plunger can be moved from its original position in the direction of a discharge opening of the device. The discharge opening is preferably located on a side of the bone cement powder that is axially opposite the discharge plunger.

The device has a delivery piston that can be moved axially in the interior space. The delivery piston is arranged on the side of the container axially opposite the discharge piston within the device. Propulsion, that is to say a relative movement of the delivery plunger in the direction of the discharge plunger, which shortens the distance between the delivery plunger and the discharge plunger within the interior space, causes the container to open. Opening of the container occurs when the distance between the delivery piston and the discharge piston is reduced in such a way that the container is subjected to a resultant force that is greater than the structural integrity of the container. As a result, the container breaks up into a large number, that is to say into at least two, of container sections, so that a monomer liquid can escape from the interior of the container into the rear part of the interior of the cartridge. Continued advancement of the delivery plunger in the direction of the discharge plunger, in particular with the cooperation of the displacement means, leads to delivery of the monomer liquid from the rear part of the interior of the device via the conduit into the front part of the interior of the device. As a result, bone cement powder and monomer liquid are brought into contact with the formation of a bone cement dough.

Within the rear of the interior of the device is stored a container containing a monomer liquid. A container of this type is understood to mean a storage option which can store the monomer liquid in a hermetically sealed and sterile manner and which can be destroyed by manual force. Examples of containers containing the monomer liquid are glass ampoules, plastic ampoules and plastic bags. Glass ampoules are preferred due to the good sterilizability and good openability by manual force.

The device has a line means by which the rear part and the front part of the interior are fluidly connected. Fluid-conducting means that the rear part and the front part of the interior are connected so that they are permeable to liquids, in particular the monomer liquid, and to gases. In order to prevent bone cement powder from getting from the front part into the rear part of the interior space and the container, or the container sections, from the rear part into the front part of the interior space via the line means, the line means is preferably equipped with a filter means, in particular one Porous disc, for example made of sintered polypropylene particles, cellulose felt or cardboard, be arranged, which designed the line means impermeable to solids. In a variant of the device, at least one passage is provided as a conduit in the discharge piston and/or between the discharge piston and the inner wall of the interior space, through which the rear part and the front part of the interior space are fluidly connected to one another. A filter impermeable to the bone cement powder and permeable to the monomer liquid and gases, for example a pore disk, for example made of sintered polypropylene particles, cellulose felt or cardboard, can be arranged in or at one or both ends of the at least one passage. In a further variant of the device, the line means is one or more lines which is or are arranged on the outside of the cartridge or in the cartridge wall and which connects the rear part and the front part of the interior space through passages in the cartridge wall or through openings. The discharge piston is bypassed in this variant.
By driving the feed piston forward in the direction of the discharge piston, the monomer liquid inside the interior of the cartridge can be transferred via the conduit from the rear part of the interior to the front part of the interior, in which the bone cement powder is located.

A variant of the device is designed such that continued advancement of the delivery piston in the direction of the discharge piston after the monomer liquid has been delivered from the rear part of the interior space to the front part of the interior space causes the discharge piston to be advanced in the direction of the discharge opening of the device. In this way, the bone cement dough provided by mixing bone cement powder and monomer liquid can be discharged from the device through the discharge opening will. This achieves in a simple manner that the bone cement dough can be expelled from the cartridge with the same drive that is also used to open the container and to deliver the monomer liquid, namely with the unidirectionally driven delivery piston.

In order to prevent the discharge piston from being pushed forward unintentionally in the direction of the discharge opening, a latching means can be arranged on the discharge piston, so that the discharge piston can latch between the front part and the rear part of the interior space with the cartridge, in particular with the cartridge wall, with this latching cannot be released by the forces occurring when the container is opened and by a pressure exerted on the monomer liquid by the delivery plunger, or by the delivery plunger and displacement means, when delivering the monomer liquid into the front part of the interior, but by direct pressure from the delivery plunger or delivery plungers , Displacement means and any container sections located in between, the pressure acting on the discharge piston can be released.
The locking means ensures that the container can first be opened by advancing the delivery plunger and the monomer liquid running out of it with the delivery plunger, or with the delivery plunger in interaction with the displacement means, can then flow into the front part of the interior of the cartridge, i.e. into the bone cement powder , Can be pressed, with the discharge piston holding its original position relative to the cartridge and the interior. Only after the monomer liquid has been largely pressed into the bone cement powder, and thus the bone cement dough is present in the front part of the interior of the cartridge, can the bone cement dough then be pressed out of the front part of the cartridge with the discharge piston. The force required to release the latch is therefore greater than the force required to open the container and convey the monomer liquid via the conduit into the front part of the interior.

When the container is opened, it breaks up into a large number of container sections, as a result of which the monomer liquid can flow into the rear part of the interior of the cartridge. It is opened by pushing the delivery plunger forward in the direction of the discharge plunger. With continued advancement, the container sections created when the container is opened can in turn break into a large number of smaller container sections. If the feed plunger has been pushed far enough in the direction of the discharge plunger, the monomer liquid begins to be conveyed from the rear part of the interior space via the line means into the front part of the interior to form the bone cement dough. A complete advance of the delivery piston, so that delivery piston and discharge piston touch each other directly, can be prevented due to the container sections, in particular if the opposite sides of the discharge piston and delivery piston are configured flat. Although the container sections can break up into smaller and smaller container sections as the conveying piston and discharge piston move closer together, there will always remain a gap between the backs of the container sections, which is filled with the monomer liquid and/or gas present in the interior. In order to convey the remaining monomer liquid in the space as completely as possible into the front part of the interior space, a volume-stable displacement means is arranged in the rear part of the interior space.

A volume-stable displacement means is to be understood as meaning a plastically and/or elastically deformable material. In particular, the displacement agent comprises a solid and/or a flowable substance with a higher viscosity than the monomer liquid. According to the invention, a material is to be regarded as volume-stable if it falls under the pressure conditions of up to 0.5 kN/cm ² occurring when using the device, in particular when opening the container, when conveying the monomer liquid and, preferably, when discharging the bone cement dough provided the device comes to no or only an insignificant change in volume of the displacement medium. Gases, for example, are not volume-stable when pressure is applied. The displacement means is suitable for enclosing the container sections under the pressure conditions acting when conveying the monomer liquid from the rear part of the interior into the front part of the interior in such a way that monomer liquid present in the space between the container sections is conveyed through the line means into the front part of the interior is in order to be available there for the formation of the bone cement dough without being conveyed into the front part of the interior. For this purpose, the displacement medium can contain at least a proportion of a solid and/or the displacement medium has such a high viscosity that conveying into the front part of the interior space through the line means, in particular through a line means equipped with a filter means, such as a porous disk, for example the pressure conditions used. The displacement means fills the space between the container sections as completely as possible, so that the monomer liquid is displaced from the space as completely as possible.

To prevent contamination of the monomer liquid by the displacer, it is preferred that the displacer be substantially insoluble in the monomer liquid, particularly methyl methacrylate, at room temperature (15 to 30°C). In particular, it is preferred that the displacement agent is soluble with a maximum of 10 g in 1 liter of methyl methacrylate at a contact time with the methyl methacrylate of 120 seconds. Preferably, the displacer does not dissolve at all in the monomer liquid, particularly methyl methacrylate.

The displacement means can comprise different materials or consist of different materials.

If the displacement means has such a plastic deformability that allows the container sections to flow around or to be enclosed under the pressure conditions used in the device, the displacement means can be designed as a plastically deformable, compact body.

An embodiment of the device is characterized in that the displacement agent comprises a hard fat and/or a wax with a melting point of at least 40°C. The displacement agent can therefore be a hard fat (adpes solidus, for example hard fat CAS 67701-26-2) with a melting point of at least 40 °C, a wax with a melting point of at least 40 °C or a mixture of hard fat with a melting point of at least 40 °C and a wax with a melting point of at least 40 °C. According to the invention, a wax is defined as paraffins, such as Fischer-Tropsch waxes (CAS 8002-74-2), amide waxes (CAS 110-30-5) or waxy fatty acid esters of natural origin, such as beeswax (CAS 18012-89-3), Roger that. The waxes can be used in pure form or with the use of plasticizers, for example from the group of fatty acid isopropyl esters or liquid paraffins. The hard fats can be used in pure form or with the addition of other compounds, such as glycerol tripalmate, glycerol trilaurate or glycerol tristearate. The melting point of the hard fat can be increased by adding glycerol trifatty acid esters that melt at more than 40 °C.

If the displacement means comprises a material that does not deform sufficiently under the given pressure conditions to form a compact body around the container sections To be able to enclose, it is preferred that the displacement means is not present as a compact body, but as a large number of particles, which are loose or bound together, for example by means of a liquid wetting the particles, ie in pasty form.

An embodiment of the device is characterized in that the displacement means comprises a large number of particles with a Shore A hardness of less than or equal to 80, preferably less than or equal to 50, more preferably less than or equal to 30. Determining the Shore A hardness of a given material is well known to those skilled in the art. Such particles can penetrate into the space between the container sections and are soft enough that when the delivery piston is advanced in the direction of the discharge piston, an elastic and/or plastic deformation of the particles takes place in the prevailing pressure conditions, so that the particles displace the cavity between the individual particles condense. This allows the monomer liquid to be displaced as completely as possible from the space between the container sections, while conveying the monomer liquid via the conduit into the front part of the interior. In addition, the container sections are surrounded as completely as possible, since the particles "snuggle up" to them.

The particles can have different shapes. A spherical particle shape is preferred because of the better flowability and associated better penetration into the space between the container sections. For example, the particles can have a spherical or ovoid particle shape.

The particles can comprise different materials or consist of different materials, as long as they have a Shore A hardness of less than or equal to 80, preferably less than or equal to 50, more preferably less than or equal to 30.

An embodiment of the device is characterized in that the particles are made of silicone rubber, natural rubber, polybutadiene-styrene rubber and/or polyurethane-polyester rubber. The particles can consist entirely or at least partially of the materials mentioned. If the particles only partially consist of the materials mentioned, it is preferable for the materials mentioned to be arranged on a surface of the particles, so that the particles can be compacted as mentioned above when the delivery piston is advanced in the direction of the discharge piston.

The particles can have different diameters.

An embodiment of the device is characterized in that the particles have a diameter in a range from 1 to 3.5 mm, preferably from 1.2 to 3.0 mm, more preferably from 1.5 to 2.5 mm. The diameter of the particles means the D50 value. Particles with these diameters allow easy insertion into the space between the container sections. In addition, such particles can be well compressed by the pressure conditions prevailing when the delivery plunger is advanced in the direction of the discharge plunger, in order to achieve the most complete possible displacement of the monomer liquid from the space between the container sections.

An embodiment of the device is characterized in that the displacement means comprises a paste containing a powdered solid and a liquid.
A large number of different materials are suitable as a powdery solid, as long as they can be brought into a paste-like form by means of a liquid and optionally further additives, for example binding agents such as cellulose, wetting agents and/or thixotropic agents. In one embodiment, the powdery solid comprises the above-described particles with a Shore A hardness of less than or equal to 80, preferably less than or equal to 50, more preferably less than or equal to 30, or consists of these particles. In a further embodiment, the powdered solid comprises a material which is harder than the particles described above.
The pulverulent solid preferably has solid particles with a diameter in a range from 1 to 3.5 mm, preferably from 1.2 to 3.0 mm, more preferably from 1.5 to 2.5 mm. The diameter of the particles means the D50 value. Solid particles with these diameters allow the paste to be easily introduced into the space between the container sections.
A large number of different liquids of an organic or inorganic nature can be used as the liquid. Examples of organic liquids include alcohols, particularly polyalcohols such as glycerin, hydrocarbons and aromatic solvents. Examples of inorganic liquids include water and aqueous solutions.

One embodiment of the device is characterized in that the paste comprises propane-1,2,3-triol (glycerol) as the liquid and silicon dioxide as the powdered solid. In a variant of the embodiment, the paste consists of silicon dioxide and propane-1,2,3-triol. An advantage of propane-1,2,3-triol is that it is non-toxic to the human body and has a high boiling point.

The silicon dioxide can have different shapes and/or properties.

An embodiment of the device is characterized in that the silicon dioxide comprises or consists of fumed silicon dioxide, precipitated silicon dioxide or a mixture of fumed and precipitated silicon dioxide.
One advantage is that pasty displacement agents can be produced particularly easily from these types of silicon dioxide due to the respective high BET surface areas.

The displacement means can occupy different volume fractions of the interior space, in particular of the rear part of the interior space.

An embodiment of the device is characterized in that the displacement means occupies a volume of displacement means which corresponds at least to a total volume of the container sections. The total volume of the container sections corresponds to the volumes of all container sections into which the container breaks up when the delivery plunger is opened or pushed forward. The total volume of the container sections therefore corresponds to a volume which corresponds to the wall of the container or the walls of the container sections per se, ie not to the space enclosed by the container. The displacement medium preferably has a displacement medium volume which corresponds to at least 1.5 times, more preferably at least 2 times, most preferably at least 2.5 times the total volume of the container sections. In this way, the container sections can be surrounded as completely as possible by the displacement means and thus the monomer liquid can be conveyed as completely as possible from the space between the tank sections into the front part of the interior. So that the interior of the cartridge and thus the device itself does not have to be designed too large and thus too unwieldy, it is preferred that the volume of the displacement medium does not correspond to more than 6 times the total volume of the container sections.

The displacement means can be arranged at different locations within the rear part of the interior of the cartridge.

An embodiment of the device is characterized in that the displacement means is arranged at least partially between the container and the delivery piston. For example, at least 10% by volume, preferably at least 25% by volume, more preferably at least 50% by volume of the displacement medium can be arranged between the container and the delivery piston. One advantage of this is that such an arrangement allows the displacement means to be easily pushed into the container sections as the delivery piston continues to be advanced in the direction of the discharge piston, since the displacement means is already pushed in the direction of the container due to its spatial arrangement. A further advantage is that the displacement means arranged in this way allows the monomer liquid to be displaced in a targeted manner in the direction of the conduit means.

An embodiment of the device is characterized in that the displacement means is arranged at least partially radially around the container. An advantage of this is that the displacer thereby exerts a stabilizing, holding effect on the container, so that it can be stored safely and with reduced risk of accidental breakage within the rear part of the interior of the cartridge. In one embodiment, the displacement means extends around the entire radial circumference of the container and thus surrounds the container like a collar. In a further embodiment, the displacement means does not extend completely around the entire radial circumference of the container, but only surrounds the container, for example over 50% of the radial circumference. In the aforementioned embodiments, the displacement element can extend over the entire length of the container or only over one or more partial lengths of the container.

In one embodiment, the delivery piston has a receptacle that is open in the direction of the container and in which the displacement means is arranged. The container is preferably partially inserted into the receptacle with an axial end pointing in the direction of the delivery plunger, so that the displacement means at least partially encloses this axial end of the container. As a result, at least at this axial end, the container is surrounded radially by the displacement means and is thus spatially fixed. In this case, the container is preferably only inserted into the receptacle to such an extent that displacement means is also arranged between the container and the delivery piston. An advantage is that in this way the reservoir is secured within the interior of the cartridge by the displacement means in such a way that the risk of accidental breakage of the reservoir, for example through jerky movements of the device, is reduced.

Preferably, no displacement means is arranged between the container and the discharge piston within the rear part of the interior of the cartridge, so that the monomer liquid does not have to be conveyed through or past the displacement means through the line means into the front part of the interior of the cartridge. This allows the monomer liquid to be conveyed into the bone cement powder with as little effort as possible by the user of the device.

1. a. Vortreiben des Förderkolbens in Richtung des Austragskolbens unter Zerfall des Behälters in eine Vielzahl an Behälterteilstücken,
2. b. Zusammenschieben der Behälterteilstücke durch fortgesetztes Vortreiben des Förderkolbens,
3. c. Verdrängen der Monomerflüssigkeit zwischen den Behälterteilstücken durch das Verdrängungsmittel unter Fördern der Monomerflüssigkeit in den vorderen Teil des Innenraums zum Ausbilden des Knochenzementteiges.

Another subject of the invention relates to a method for preparing a bone cement dough from two starting components by means of a device, in particular by means of a device according to one of the preceding embodiments, comprising the following steps:

1. a. advancing the delivery plunger in the direction of the discharge plunger, with the container breaking up into a large number of container sections,
2. b. Pushing the container sections together by continuing to advance the delivery plunger,
3. c. displacing the monomer liquid between the container sections by the displacing means while feeding the monomer liquid into the front part of the inner space to form the bone cement dough.

Depending on the container used, for example when using a glass ampoule as a container, pushing together the container sections created when the container is opened can lead to further fragmentation of the container sections, or at least one or more of the initial container sections, into further, smaller container sections. Irrespective of this further fragmentation, there will always remain a space between the container sections in which at least part of the monomer liquid remains. If the container sections cannot be pushed together any further by further advancement of the delivery piston in the direction of the discharge piston, the displacement agent stored in the rear part of the interior is introduced into the space between the container sections at this point at the latest. The displacement means will accommodate the container sections by enclosing them and thereby displace the monomer liquid remaining in the intermediate space from the intermediate space. The displacement means is preferably designed in such a way that it essentially cannot absorb the monomer liquid. Since the rear part of the interior space is closed at one axial end by the delivery plunger, only the monomer liquid remains the path through the conduit into the front part of the interior. There it comes into contact with the bone cement powder to form the bone cement dough.

The delivery plunger can be advanced in different ways in the direction of the discharge plunger into the cartridge. For example, a user of the device can advance the delivery piston manually, in particular by applying force to a rod or axis. In a further embodiment, the cartridge and the delivery plunger together form a thread, via which the delivery plunger can be screwed into the cartridge in the direction of the discharge plunger. The cartridge preferably has an internal thread and the delivery piston has an external thread, which interact in a form-fitting and/or non-positive manner in order to enable the delivery piston to be advanced.

In a further embodiment of the method, the delivery plunger is advanced using a mechanical aid.

One embodiment of the method is characterized in that the device is inserted into a discharge device, in particular a discharge gun for bone cement dough, in order to advance the delivery plunger. Discharge guns for bone cement dough are known to those skilled in the art.

When the monomer liquid is conveyed from the rear part to the front part of the interior, the formation of the bone cement dough from the two starting components begins. This preferably takes place with the two starting components being mixed as uniformly as possible in order to obtain a bone cement dough which is as homogeneous as possible. The mixing of the two components can be done in different ways. In one embodiment of the method, the mixing takes place with the active participation of the user of the device, for example by shaking the device or by actuating a mixing element in the front part of the interior, in particular a stirrer.

An embodiment of the method is characterized in that the monomer liquid is distributed in the bone cement powder with the aid of a hydrophilic additive. An advantage is that this is done without active involvement of the user of the device, avoiding possible user error during mixing. A possible mistake is that the user does not cover the entire length of the front part of the Interior mixes so that parts of the bone cement powder are not wetted with monomer liquid. A further advantage is that the device can thereby be configured more simply and with fewer moving parts, which reduces both the risk of malfunctions and the manufacturing costs of the device.

The device according to the invention is characterized in that it provides a bone cement dough from two starting components. Bone cement dough is understood to be a substance that is suitable in the field of medical technology for creating a stable connection between artificial joints, such as hip and knee joints, and bone material. Hardening turns bone cement dough into bone cement. These bone cements are preferably polymethyl methacrylate bone cements (PMMA bone cements). PMMA bone cements have long been used in medical applications and go back to the work of Sir Charnley (cf. Charnley, J. Anchorage of the femoral head prosthesis of the shaft of the femur. J. Bone Joint Surg. 1960; 42, 28-30 .). PMMA bone cements can be produced from a bone cement powder as the first starting component and a monomer liquid as the second starting component. With a suitable composition, the two starting components can be stored separately from one another. When the two starting components are brought into contact, the swelling of the polymer components of the bone cement powder results in a plastically deformable bone cement dough. In this case, polymerization of the monomer is initiated by free radicals. As the polymerization of the monomer progresses, the viscosity of the bone cement paste increases until it hardens completely.
A bone cement powder is understood to mean a powder which comprises at least one particulate polymethyl methacrylate and/or one particulate polymethyl methacrylate copolymer. Examples of copolymers are styrene and/or methyl acrylate. In one embodiment, the bone cement powder can additionally include a hydrophilic additive, which supports the distribution of the monomer liquid within the bone cement powder. In a further embodiment, the bone cement powder can additionally comprise an initiator which initiates the polymerisation. In a further embodiment, the bone cement powder can additionally include an X-ray opaque material. In yet another embodiment, the bone cement powder can additionally include pharmaceutically active substances such as antibiotics.

The bone cement powder preferably comprises at least one particulate polymethyl methacrylate and/or one particulate polymethyl methacrylate copolymer, an initiator and an X-ray opaque material as a hydrophilic additive, or consists of these components. More preferably, the bone cement powder comprises at least one particulate polymethyl methacrylate and/or a particulate polymethyl methacrylate copolymer, an initiator, an X-ray opaque material and a hydrophilic additive or consists of these components. Most preferably, the bone cement powder comprises or consists of at least one particulate polymethyl methacrylate and/or a particulate polymethyl methacrylate copolymer, an initiator, a radiopaque, a hydrophilic additive and an antibiotic.
According to the invention, the particle size of the particulate polymethyl methacrylate and/or the particulate polymethyl methacrylate copolymer of the bone cement powder can correspond to the sieve fraction of less than 150 μm, preferably less than 100 μm.
According to the invention, the hydrophilic additive can be particulate and/or fibrous. In a further embodiment, the hydrophilic additive can be sparingly soluble, preferably insoluble, in methyl methacrylate. In a further embodiment, the hydrophilic additive can have an absorption capacity of at least 0.6 g of methyl methacrylate per gram of hydrophilic additive. In a further embodiment, the hydrophilic additive can have a chemical substance with at least one OH group. It can preferably be provided that the hydrophilic additive has covalently bonded OH groups on its surface. Examples of such preferred hydrophilic additives can be additives selected from the group comprising cellulose, oxycellulose, starch, titanium dioxide and silicon dioxide, with pyrogenic silicon dioxide being particularly preferred. In one embodiment, the particle size of the hydrophilic additive of the sieve fraction can correspond to less than 100 μm, preferably less than 50 μm and most preferably less than 10 μm. The hydrophilic additive can be contained in an amount of 0.1 to 2.5% by weight based on the total weight of the bone cement powder.
According to the invention, the initiator can contain dibenzoyl peroxide or consist of dibenzoyl peroxide.
According to the invention, an X-ray opaque is a substance that allows the bone cement to be made visible on X-ray diagnostic images. Examples of radiopacifiers can include barium sulfate, zirconia, and calcium carbonate. According to the invention, the pharmaceutically active substance can comprise one or more antibiotics and optionally added cofactors for the one or more antibiotics. The pharmaceutically active substance preferably consists of one or more antibiotics and optionally added cofactors for the one or more antibiotics. Examples of antibiotics include gentamicin, clindamycin, and vancomycin. According to the invention, the monomer liquid can comprise the monomer methyl methacrylate or consist of methyl methacrylate. In one embodiment, the monomer liquid comprises, in addition to the monomer, an activator dissolved therein, such as N,N-dimethyl-p-toluidine, or consists of methyl methacrylate and N,N-dimethyl-p-toluidine.

The features disclosed for the device are also disclosed for the method and vice versa.

characters

The invention is further illustrated by way of example in the following by figures. The invention is not limited to the figures.

Fig. 1

einen schematischen Querschnitt einer Vorrichtung zum Bereitstellen eines Knochenzementteigs,

Fig. 2

einen schematischen Querschnitt der Vorrichtung aus Figur 1 nach einem beginnenden Vortreiben eines Förderkolbens in Richtung eines Austragskolbens,

Fig. 3

einen schematischen Querschnitt der Vorrichtung aus den Figuren 1 und 2 nach einem Öffnen eines Behälters 300,

Fig. 4

einen schematischen Querschnitt der Vorrichtung aus den Figuren 1 bis 3 beim beginnenden Fördern einer Monomerflüssigkeit,

Fig. 5

einen schematischen Querschnitt der Vorrichtung aus den Figuren 1 bis 4 nach erfolgtem Fördern der Monomerflüssigkeit, und

Fig. 6

einen schematischen Querschnitt der Vorrichtung aus den Figuren 1 bis 5 beim Austragen des Knochenzementteigs.

Show it

1

a schematic cross section of a device for providing a bone cement dough,

2

a schematic cross-section of the device figure 1 after a delivery plunger begins to be driven forward in the direction of a discharge plunger,

3

a schematic cross section of the device from the figures 1 and 2 after opening a container 300,

4

a schematic cross section of the device from the Figures 1 to 3 at the beginning of conveying a monomer liquid,

figure 5

a schematic cross section of the device from the Figures 1 to 4 after the monomer liquid has been conveyed, and

6

a schematic cross section of the device from the Figures 1 to 5 when discharging the bone cement dough.

Description of the figures

figure 1 shows a schematic cross section of an exemplary embodiment of a device 100 for preparing a bone cement dough in an initial state. The device 100 is in one piece, but is made up of several components. The device 100 has a tubular structure and includes a hollow-cylindrical cartridge 200 with an interior 210. In a front part 220 of the interior 210 is a bone cement powder 400 as a first starting component and in a rear part 230 of the interior 210 is a container 300 in the form of a glass ampoule containing a monomer liquid 350 stored as the second starting component of the bone cement paste. The main component of the bone cement powder 400 is particulate polymethyl methacrylate and also a hydrophilic additive with which the monomer liquid 350 can be distributed in the bone cement powder 400 .
The front part 220 and the rear part 230 of the interior space 210 are separated by a discharge piston 250 that can move axially in the interior space 210 . The discharge piston 250 is designed to be impermeable to solids, so that no bone cement powder 400 from the front Part 210 can not get into the rear part 230 of the interior 210 and the container 300 from the rear part 230 in the front part 220 of the interior 210.
The discharge plunger 250 has a conduit 260 in the form of a plurality of passages through which there is a fluid-conducting connection between the front part 220 and the rear part 230 . In the embodiment of the device 100 shown, the conduit means 260 is formed as part of the discharge plunger 250 . In further embodiments that are not shown, the line means 260 can be formed separately from the discharge plunger 250, for example as a tubular line outside the cartridge. The conduit 260 is sealed by a porous disc 265 for solids and highly viscous liquids, such as hard fats, waxes, pastes or bone cement dough, which, however, allows the monomer liquid 350 to be conveyed from the rear part 230 to the front part 220 of the interior space 210 without any problems. In the embodiment of the device 100 shown, the porous disk 265 is arranged on the end of the conduit 260 facing the front part 220 of the interior space 210 . In further, not shown, embodiments, the porous disc 265 or other type of means is arranged on the end of the conduit means 260 facing the rear part 230 or on both ends of the conduit means 260 . An advantage of a porous disc arranged as shown is that the bone cement dough forming at the front part 220 of the interior space 210 cannot clog the conduit means 260 .
On the side of the container 300 opposite the discharge piston 250 there is a delivery piston 270 which can move axially within the interior space 210 . The delivery plunger 270 closes off a rear side of the interior 210 of the cartridge 200 .
So that monomer liquid 350 that has escaped from the container 300 is not pressed past the discharge piston 250 into the front part 220 of the interior space 210, two radially circumferential sealing rings 255 made of rubber are provided on the discharge piston 250, with which the discharge piston 250 is sealed against the wall of the interior space 210 . Likewise, two radially circumferential sealing rings 275 are provided on the delivery plunger 270, with which an escape of the monomer liquid 350 past the delivery plunger 270 and out of the device 100 is avoided. The sealing effect of the sealing rings 275 on the delivery plunger 270 must be sufficient, even if the delivery plunger 270 exerts such great pressure on the monomer liquid 350 that it flows through the conduit 270 and the porous disc 265 from the rear part 230 into the front part 220 of the interior 210 is pressed in.
The device also has a discharge opening 280 which delimits the area of the front part 220 of the interior 210 of the cartridge 200 which faces away from the discharge plunger 250 . In the initial state of the device 100 , the discharge opening 280 is closed by a sealing cap 281 with a plug 285 , so that no bone cement powder 400 can escape from the cartridge 200 .
A displacement means 500 is mounted within the rear part 230 of the interior space 210 . In the embodiment shown, the displacement means 500 is arranged within a receptacle 271 of the delivery piston 270 in the initial state of the device 100 . The displacement means 500 arranged in this way surrounds part of the container 300, in particular a container head 310 in the form of a glass ampoule head, both axially in the direction of the delivery plunger 270 and radially. The container 300 is thus fixed within the rear part 230 of the interior 210 by means of the discharge piston 250 and the displacement means 500 in such a way that the risk of accidentally opening the container 300, for example due to a shaking-like movement of the device 100, is reduced. The type of arrangement shown is particularly suitable for displacement means 500 which are present as a compact, plastically deformable body, for example in the form of a hard fat, as a wax or in a paste-like form.
In the embodiment shown, the device 100 is inserted into a discharge device 700 (not fully shown). The discharge device comprises an internal thread 710, which interacts positively and/or non-positively with an external thread 110 of device 100 and thus connects device 100 and discharge device 700 to one another, and a plunger 720. Device 100 and discharge device 700 are not in further, non-illustrated embodiments via a thread, but via a different type of connection in a form-fitting and/or force-fitting manner, in particular via a bayonet catch or a plug-in connection. The delivery plunger 270 can be advanced axially in the interior space 210 in the direction of the discharge plunger 250 by means of the ram 720 in the direction of the discharge plunger 250 .

figure 2 shows the device figure 1 , where compared to figure 1 the delivery plunger 270 is advanced by means of the plunger 720 of the discharge device 700 in the direction of the delivery plunger 250 until the container 300 and delivery plunger 270 come into contact. In the process, the container 300 , in particular the container head 310 , was further accommodated in the receptacle 271 of the delivery piston 270 , while at the same time part of the displacement means 500 was pushed out of the receptacle 271 . The position of the discharge piston 250 is compared to figure 1 essentially unchanged. The distance between the delivery plunger 270 and the discharge plunger 250 essentially corresponds to the length of the container 300 in the state of the device 100 shown.

figure 3 shows the device 100 of FIGS figures 1 and 2 , where compared to figure 2 the delivery plunger 270 is driven further in the direction of the discharge plunger 250 by means of the plunger 720 of the discharge device 700 . The structural integrity of the container 300 was destroyed by the advancement of the delivery piston 270, as a result of which it disintegrated into a plurality of container sections 300a and the monomer liquid 350 escaped from the interior of the container 300 into the rear part 230 of the inner space 210. Some of the container sections 300a are at least partially enclosed by the displacement means 500 so that no monomer liquid 350 can be found between them. Between other container sections 300a not enclosed by the displacement means 500, monomer liquid 350 can be found. The monomer liquid is arranged between the displacement means 500 and the discharge piston 250 within the rear part 230 of the inner space 210 .

figure 4 shows the device 100 of FIGS Figures 1 to 3 , where compared to figure 3 the delivery piston 270 is driven further in the direction of the discharge piston 250. Due to the resulting reduced distance from delivery piston 270 to discharge piston 250, the in figure 3 shown container sections 300a at least partially burst into further, smaller container sections 300a. The displacement means 500 encloses compared to figure 3 a greater proportion of tank sections 300a, thereby displacing the monomer liquid 350 between these tank sections 300a. The delivery plunger 270 has been inserted so far into the cartridge 200 that the monomer liquid 260 has penetrated into the conduit 260 .

figure 5 shows the device 100 of FIGS Figures 1 to 4 , where compared to figure 4 the delivery piston 270 is driven further in the direction of the discharge piston 250. As a result of the advancing, the container sections 300a are essentially completely surrounded by the displacement means 500 and the monomer liquid 350 from the Figures 1 to 4 been funded substantially completely via the line means 260 from the rear part 230 in the front part 220 of the interior 210, whereby the bone cement powder 400 from the Figures 1 to 4 and the monomer liquid 350 formed and provided a bone cement dough 450 in the front part 220 of the inner space 210 . To support this, the bone cement powder 400 has an additive with which it is possible to introduce the monomer liquid 350 at a base area of the front part 220 of the interior space 210 and still achieve complete distribution of the monomer liquid 350 in the bone cement powder 400 . The porous disc 260 prevents the displacement agent 500 from being conveyed into the bone cement dough 450. In the

During the formation of the bone cement dough 450 from monomer liquid 350 and bone cement powder 400, swelling of the bone cement powder 400 led to an increase in volume of the original bone cement powder 400, as a result of which the plug 285 was partially expelled from the closure cap 281.

figure 6 shows the device 100 of FIGS Figures 1 to 5 , where compared to figure 5 the delivery plunger 270 together with the discharge plunger 250 has been advanced in the direction of the discharge opening 281 of the device 100 . The bone cement dough 450 has been partially discharged from the device 100 as a result of the driving forward. In order to carry out the discharge in a targeted manner, the cap 281 is made of the Figures 1 to 5 replaced by a 730 discharge snorkel (only partially shown). In further, not shown embodiments, the bone cement dough without discharge snorkel 730, for example by simply removing the plug 285 or the plug 285 and the cap 281 from the Figures 1 to 5 discharged from the device 100.

figure 7 shows a method 600 for providing a bone cement dough 450 from two starting components by means of the device 100 according to FIGS Figures 1 to 6 comprising the method steps 610 to 630 and optionally 640.

In a step 610 the delivery plunger 270 is pushed into the cartridge 200 in the direction of the discharge plunger 250 . If the distance between the delivery plunger 270 and the discharge plunger 250 falls below the length of the container 300, it breaks up into at least two container sections 300a, so that the monomer liquid 350 can flow out into the rear part 230 of the interior space 210. The discharge piston 250 essentially remains in the same position within the interior space 210.

In a step 620, continued advancement of the delivery plunger 270 toward the discharge plunger 250 compresses the initial container sections 300a. As a result of the compression, the initial container sections 300a can disintegrate into smaller container sections 300a depending on the distance between the delivery piston 270 and the discharge piston 250 .

At the latest when the volume of the rear part 230 of the interior space 210 decreases below the volume of the monomer liquid 350, the monomer liquid 350 begins to be pumped via the conduit 260 into the front part 220 of the interior space 210 with the beginning formation of the bone cement dough 450 .

In a step 630, the monomer liquid between the container sections 300a is displaced by the displacement means 500 while the delivery plunger 270 continues to be advanced in the direction of the discharge plunger 250. For this purpose, the delivery piston 270 brings the displacement means 500 under pressure into an intermediate space between the container sections 300a, so that the displacement means 500 encloses the container sections 300a as far as possible and the monomer liquid 350 from the intermediate space between the container sections 300a via the line means 260 into the front part 220 of the interior 210 is promoted.

For this purpose, the displacement means 500 has a volume which can if possible fill the entire space between the container sections 300a, so that if possible the entire monomer liquid 350 can be conveyed into the front part 220 of the interior and is available there for forming the bone cement dough.

In an optional step 640, the bone cement dough 450 is discharged from the device 100 through a discharge opening 280 in the front part 220 of the interior space 210 by the continued forward drive 610 of the delivery piston 270 . For this purpose, the delivery plunger 270 overcomes a force holding the discharge plunger 250 so that the delivery plunger 270 and the discharge plunger 250 are moved together in the direction of the discharge opening 280 within the interior space 210 and the bone cement dough 450 is discharged.

As a result, the container 300 is opened, the monomer liquid 350 is conveyed as completely as possible into the front part 220 of the interior space 210 with the cooperation of the displacement means 500 and optionally the bone cement dough 450 provided thereby is discharged with a unidirectional linear movement of the delivery piston 270 in the interior space 210 of the cartridge 200

In order to provide a bone cement dough 450 with as few air inclusions as possible, the device 100 is preferably held during steps 610 to 630 in such a way that the discharge piston 250 is spatially arranged above the delivery piston 270 . Thus, from the rear part 230 of the interior space 210, gas present there, such as air or an inert gas, in particular nitrogen or argon, is first conveyed via the line 260 into the front part 220 of the interior space 210, before the monomer liquid 350 uses. In this way, gas inclusions in the bone cement powder 400 are displaced by the monomer liquid 350 and no further gas is introduced once the bone cement dough 450 has started to form.

The advancement 610 of the delivery plunger 270 can take place through the manual application of force by a user of the device 100 . In a preferred embodiment of the method 600, the device 100 is inserted into a discharge device 700 for the propulsion 610 and the delivery plunger 270 is advanced by actuating the discharge device 700, for example a discharge gun. This makes it easier for the user to use the device 100.

Reference sign

100

contraption

110

external thread

200

hollow cylindrical cartridge

210

Interior of the cartridge

220

front part of the interior

230

rear part of the interior

250

discharge plunger

255

Sealing rings of the discharge piston

260

line means

265

porous disc

270

delivery plunger

271

recording

275

Sealing rings of the feed piston

280

discharge opening

281

sealing cap

285

Plug

300

container

300a

container sections

310

container head

350

monomer liquid

400

bone cement powder

450

bone cement dough

500

displacer

600

Method of providing a bone cement dough

610

propel

620

pushing together

630

Push away

700

discharge device

710

inner thread

720

pestle

730

discharge snorkel

Claims (16)

Device (100) for preparing a bone cement paste (450) from two starting components, comprising
a hollow-cylindrical cartridge (200) with an interior (210), wherein in a front part (220) of the interior (210) a bone cement powder (400) as the first starting component and in a rear part (230) of the interior (210) a container ( 300) containing a monomer liquid (350) stored as the second starting component,
between the bone cement powder (400) and the container (300) a discharge piston (250) movable axially in the interior (210) and on the side of the container (300) opposite the discharge piston (250) a delivery piston ( 270), the rear part (230) and the front part (220) of the interior (210) being connected to one another in a fluid-conducting manner via a line (260) and by advancing the delivery piston (270) in the direction of the discharge piston (250) the container (300) can be opened by breaking it up into a large number of container sections (300a), so that the monomer liquid (350) can flow into the rear part (230) of the interior (210),
characterized in that
A volume-stable displacement means (500) is arranged in the rear part (230) of the interior (210), which is designed to move the container sections (300a) with progressive advancement of the delivery piston (270) in the direction of the discharge piston (250) with displacement of the monomer liquid between the To enclose container sections (300a) in order to convey the monomer liquid (350) from the rear part (230) via the line means (260) into the front part (220) of the interior (210). The device (100) of claim 1, wherein the displacing agent (500) is substantially insoluble in the monomer liquid (350) at room temperature. The device (100) of claim 1 or 2, wherein the displacing agent (500) comprises a hard fat and/or a wax having a melting point of at least 40°C. Device (100) according to one of claims 1 or 2, wherein the displacement means (500) comprises a multiplicity of particles with a Shore A hardness of less than or equal to 80, in particular less than or equal to 30. Device (100) according to claim 4, wherein the particles are spherical, in particular spherical or ovoid. Device (100) according to claim 4 or 5, wherein the particles are formed from silicone rubber, natural rubber, polybutadiene-styrene rubber and/or polyurethane-polyester rubber. A device (100) according to any one of claims 4 to 6, wherein the particles have a diameter in the range 1 to 3.5 mm. The device (100) according to claim 1 or 2, wherein the displacement means (500) comprises a paste containing a powdered solid and a liquid. The device (100) of claim 8, wherein the liquid comprises propane-1,2,3-triol and the solid comprises silicon dioxide. The device (100) of claim 9, wherein the silicon dioxide comprises at least one of fumed silicon dioxide and precipitated silicon dioxide. Device (100) according to one of the preceding claims, wherein the displacement means (500) occupies a volume of displacement means which corresponds at least to a total volume of the container sections (300a). Device (100) according to one of the preceding claims, wherein the displacement means (500) is arranged at least partially between the container (300) and the delivery piston (270). Device (100) according to one of the preceding claims, wherein the displacement means (500) is arranged at least partially radially around the container (300). Method (600) for providing a bone cement dough (450) from two starting components by means of a device (100) according to one of the preceding claims, comprising the following steps: a. Driving (610) the delivery plunger (270) in the direction of the discharge plunger (250) with the container (300) breaking up into a large number of container sections (300a), b. Pushing together (620) of the container sections (300a) by continued advancement (610) of the delivery piston (270), c. Displacing (630) the monomer liquid (350) between the container sections (300a) by the displacement means (500) while conveying the monomer liquid (350) into the front part (220) of the inner space (210) to form the bone cement dough (450). Method (600) according to Claim 14, in which the device (100) is inserted into a discharge device (700) in order to advance (610) the delivery piston (270). The method (600) according to claim 14 or 15, wherein the monomer liquid (350) is distributed in the bone cement powder (400) with the aid of a hydrophilic additive.

Images